The present invention relates to cementitious components and, more particularly, in certain embodiments, to methods of determining a reactive index for cementitious components.
In general, well treatments include a wide variety of methods that may be performed in oil, gas, geothermal and/or water wells, such as drilling, completion and workover methods. The drilling, completion and workover methods may include, but are not limited to, drilling, fracturing, acidizing, logging, cementing, gravel packing, perforating and conformance methods. Many of these well treatments are designed to enhance and/or facilitate the recovery of desirable fluids from a subterranean well. These fluids may include hydrocarbons such as oil and/or gas.
In cementing methods, such as well construction and remedial cementing, settable compositions are commonly utilized. As used herein, the term “settable composition” refers to a composition(s) that hydraulically sets or otherwise develops compressive strength. Settable compositions may be used in primary cementing operations whereby pipe strings, such as casing and liners, are cemented in well bores. In performing primary cementing, a settable composition may be pumped into an annulus between a subterranean formation and the pipe string disposed in the subterranean formation or between the pipe string and a larger conduit disposed in the subterranean formation. The sellable composition should set in the annulus, thereby forming an annular sheath of hardened cement (e.g., a cement sheath) that should support and position the pipe string in the well bore and bond the exterior surface of the pipe string to the walls of the well bore or to the larger conduit. Sellable compositions also may be used in remedial cementing methods, such as the placement of cement plugs, and in squeeze cementing for sealing voids in a pipe string, cement sheath, gravel pack, formation, and the like. Sellable compositions may also be used in surface applications, for example, construction cementing.
Settable compositions for use in subterranean formations may typically include a cementitious component which hydraulically sets, or otherwise hardens, to develop compressive strength. Examples of cementitious components that can be included in settable compositions include Portland cement, calcium aluminate cement, cement kiln dust, lime kiln dust, fly ash, slag, pumice, and rice-hull ash, among others. The performance of these different cementitious components in settable compositions may vary and can even vary for a particular cementitious component depending, for example, on the particular type or source of the component. For example, certain of these cementitious components may have undesirable properties that can make them unsuitable for use in well treatments. In addition, variation of the performance for the cementitious components can lead to lack of predictability and consistency for the cementitious components when used in treatment fluids. This lack of predictability consistency may even be apparent for the same cementitious component, for example, if sourced from different locations.